T. B. R0SSETER ON CYSTICERCUS OF TJ1NIA LIOPHALLU8. 317 



which species of tape-worm the hook of the Cysticercus belongs 

 in its final stage, and it is on such demonstrable proofs that we 

 mainly rely in classifying oar Cysticercoids. In this instance 

 we have another point to guide us, and which of itself serves to 

 sharply define the two species of Cysticerci, viz., the diameter 

 of the cyst (Figs. 13 and 17). 



Cysticercus liophallus, diameter of cyst ... 0*290 mm. 

 ,, setigera ,, ,, ... 0*125 mm. 



0*165 mm. 



This measurement shows that the cyst of C. liophallus is 

 0*165 mm. larger than that of C. setigera. This, in my opinion, 

 together with the difference that exists between the hooks of 

 each species, establishes this Cysticercus as being the Cysti- 

 cercus of Tcenia liophallus. 



This is the first recorded instance of the finding of the 

 Cysticercus or intermediate stage of the above tape- worm. 



When the Cysticercus extruded itself from the body cavity 

 of the Cypris owing to the pressure applied to this and other 

 Ostracoda and Copepoda, the caudal appendage was wanting ; 

 evidently it had been severed from the cyst by the sudden 

 pressure applied. When the carapace of the Cypris is crushed 

 the Cysticercus shoots out from the body cavity of its nurse, 

 and is held in check by the caudal appendage. It is marvellous 

 how great is the tension of the caudal appendage before the 

 breaking-strain, which severs the caudal appendage from the 

 Cypris, is reached. 



I can give no information as to the formation of the scolex, 

 suckers or rostrum in this, the Cysticercoid stage, as I acci- 

 dental^ crushed the cyst during examination, and the plasmic 

 substance exuded was of such a diffluent, undefinable character 

 that it was impossible to trace anything distinctive. Evidently 

 it was in an early stage of formation. I only found one speci- 

 men of this Cysticercus. 



